Welcome to the symposium! We will introduce you to an overview of our symposium's schedule, and present information for the symposium's raffle.
11 am – 12 pm: Dark Matter Theories and Hypotheses
Cosmic mysteries and the hydrogen 21-cm line
The forbidden 21cm line of atomic hydrogen could help us solve some of the remaining mysteries of our Universe.
For example, it could advance our understanding of the nature of dark matter, the formation process of the very first stars and galaxies, constrain primordial black holes and clarify the ultimate phase transition that the Universe went through — the process of reionization. The field of the 21cm cosmology is undergoing a revolution with both observations and modelling making rapid progress.
At present only one experiment (EDGES Low Band) has claimed a tentative detection of the sky-averaged 21cm signal which, however, disagrees with standard theoretical predictions. Other experiments yield upper limits which allow to exclude physically motivated models and constrain on the thermal and ionization states of the gas at high cosmological redshifts. In my talk, I will describe what we can learn from the 21-cm line about the nature of dark matter.
—Dr. Anastasia Fialkov, University of Cambridge
2 pm – 3 pm
Hubble Tension & Dark Energy
Edwin Hubble discovered in the late 1920s that the Universe is expanding. Over the past few years, though, increasingly precise measurements of the rate at which the Universe is expanding disagree. I will describe these measurements and the discrepancy between the rates returned by different techniques. I will then describe the implications for cosmology if these discrepancies persist.
—Professor Marc Kamionkowski, Johns Hopkins University
A question-and-answer about dark matter and contrasting theories by research astronomers. Ask your most thoughtful, burning questions about dark matter in the universe!
—WithProfessors Miriam Diamond (Professor of Astroparticle Physics at the University of Toronto); Jeremy Webb (Assistant Professor of Astronomy & Astrophysics at the University of Toronto); and Jim Cline (Professor of Physics at McGill University), with moderator Alex Laguë (Astrophysics PhD Student at the University of Toronto)
7 pm – 8 pm
February 16 Black Hole Lecture: Black holes, quantum information, and string theory
Quantum theory is one of the pillars of 20th century physics: it successfully describes the dynamics of very small things, like electrons in a silicon chip and Higgs bosons in the LHC particle collider. Einstein's general theory of relativity is another pillar: it successfully describes the dynamics of very heavy things, like planets, stars, and the entire cosmos. But at a deep theoretical level, these two theories are incompatible. This is a problem if we want to understand physical phenomena that are both very small and very heavy, like black holes and the big bang. To analyze their physics, we need a working theory of quantum gravity.
My research focuses on learning about quantum gravity by using techniques of modern string theory. I especially want to know precisely what happens to quantum information falling into black holes, and to resolve a famous paradox about this posed by Stephen Hawking forty-five years ago and refined by many other researchers since. To study such questions, I currently use a powerful theoretical laboratory known as AdS/CFT holography, whose discovery was one of the most important advances in theoretical physics in the past quarter century. No previous experience with any of these topics will be assumetd and all are welcome.
Einstein's Monsters are regions of space and time excised from the rest of the universe. Black holes were predicted a century ago, and it took decades of research to show that they actually exist. More recently, astronomers have discovered black hole behemoths inside galaxies that range up to billions of times the Sun's mass, and they have detected gravitational waves from black hole mergers. The talk covers progress in understanding black holes and mysteries that remain.
For millennia, humans have looked to the sky in wonder of what lay beyond our minuscule grain of sand in the vast desert that is the universe. To them the distant stars were mere specks of light settled upon a moving blanket sheathing the sky, but of course, we have come a long way since then. From the history of astrophotography, to large equipment, to the tools you have laying around your home, I will immerse you into the world of imaging the absolute beasts of cosmological objects of which we are so fascinated.
—Katerina Isabel Benevides, University of Toronto Astrophysics Specialist